{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T13:40:42Z","timestamp":1777642842987,"version":"3.51.4"},"reference-count":41,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2026,1,21]],"date-time":"2026-01-21T00:00:00Z","timestamp":1768953600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002969","name":"Technology Agency of the Czech Republic","doi-asserted-by":"publisher","award":["TM04000062"],"award-info":[{"award-number":["TM04000062"]}],"id":[{"id":"10.13039\/501100002969","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Taiwan National Science and Technology Council","award":["NSTC-112-2923-H-011-001-MY3"],"award-info":[{"award-number":["NSTC-112-2923-H-011-001-MY3"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["MPs"],"abstract":"<jats:p>This study presents a standardized method for multimodal monitoring of exercise execution in isolated, confined, and extreme (ICE) environments, addressing the need for reproducible assessment of neuromuscular and cardiovascular responses under space- and equipment-limited conditions. The method integrates wearable surface electromyography (sEMG), inertial measurement units (IMU), and electrocardiography (ECG) to capture muscle activation, movement, and cardiac dynamics during space-efficient exercise. Ten exercises suitable for confined habitats were implemented during analog missions conducted in the DeepLabH03 facility, with feasibility evaluated in a seven-day campaign involving three adult participants. Signals were synchronized using video-verified repetition boundaries, sEMG was normalized to maximum voluntary contraction, and sEMG amplitude- and frequency-domain features were extracted alongside heart rate variability indices. The protocol enabled stable real-time data acquisition, reliable repetition-level segmentation, and consistent detection of muscle-specific activation patterns across exercises. While amplitude-based sEMG indices showed no uniform main effect of exercise, robust exercise-by-muscle interactions were observed, and sEMG mean frequency demonstrated sensitivity to differences in movement strategy. Cardiac measures showed limited condition-specific modulation, consistent with short exercise bouts and small sample size. As a proof-of-concept feasibility study, the proposed protocol provides a practical and reproducible framework for multimodal physiological monitoring of exercise in ICE analogs and other constrained environments, supporting future studies on exercise quality, training load, and adaptive feedback systems. The protocol is designed to support near-real-time monitoring and forms a technical basis for future exercise-quality feedback in confined habitats.<\/jats:p>","DOI":"10.3390\/mps9010015","type":"journal-article","created":{"date-parts":[[2026,1,21]],"date-time":"2026-01-21T08:48:08Z","timestamp":1768985288000},"page":"15","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Multimodal Wearable Monitoring of Exercise in Isolated, Confined, and Extreme Environments: A Standardized Method"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2461-6283","authenticated-orcid":false,"given":"Jan","family":"Hejda","sequence":"first","affiliation":[{"name":"Faculty of Biomedical Engineering, Czech Technical University in Prague, 27201 Kladno, Czech Republic"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5795-7581","authenticated-orcid":false,"given":"Marek","family":"Sokol","sequence":"additional","affiliation":[{"name":"Faculty of Biomedical Engineering, Czech Technical University in Prague, 27201 Kladno, Czech Republic"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3460-7914","authenticated-orcid":false,"given":"Lydie","family":"Leov\u00e1","sequence":"additional","affiliation":[{"name":"Faculty of Biomedical Engineering, Czech Technical University in Prague, 27201 Kladno, Czech Republic"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7230-7421","authenticated-orcid":false,"given":"Petr","family":"Volf","sequence":"additional","affiliation":[{"name":"Faculty of Biomedical Engineering, Czech Technical University in Prague, 27201 Kladno, Czech Republic"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jan","family":"Tonner","sequence":"additional","affiliation":[{"name":"Faculty of Biomedical Engineering, Czech Technical University in Prague, 27201 Kladno, Czech Republic"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wei-Chun","family":"Hsu","sequence":"additional","affiliation":[{"name":"Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yi-Jia","family":"Lin","sequence":"additional","affiliation":[{"name":"Graduate Institute of A.I. Cross-Disciplinary Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8814-1275","authenticated-orcid":false,"given":"Tommy","family":"Sugiarto","sequence":"additional","affiliation":[{"name":"Industrial Technology Research Institute, Hsinchu 310, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0584-4523","authenticated-orcid":false,"given":"Miroslav","family":"Rozlo\u017en\u00edk","sequence":"additional","affiliation":[{"name":"Hydronaut Project a.s., 15500 Prague, Czech Republic"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4160-9851","authenticated-orcid":false,"given":"Patrik","family":"Kut\u00edlek","sequence":"additional","affiliation":[{"name":"Faculty of Biomedical Engineering, Czech Technical University in Prague, 27201 Kladno, Czech Republic"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1016\/j.actaastro.2021.05.005","article-title":"Effectiveness of exercise countermeasures for the prevention of musculoskeletal deconditioning in simulated hypogravity: A systematic review","volume":"185","author":"Swain","year":"2021","journal-title":"Acta Astronaut."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1186\/s40798-017-0107-y","article-title":"The effect of long-term confinement and the efficacy of exercise countermeasures on muscle strength during a simulated mission to Mars: Data from the Mars500 study","volume":"3","author":"Gaffney","year":"2017","journal-title":"Sport. Med.\u2014Open"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1489","DOI":"10.1080\/001401300750003925","article-title":"Aerobic performance of Special Operations Forces personnel after a prolonged submarine deployment","volume":"43","author":"Fothergill","year":"2000","journal-title":"Ergonomics"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1077","DOI":"10.1152\/japplphysiol.00622.2016","article-title":"Recovery of the immune system after exercise","volume":"122","author":"Peake","year":"2016","journal-title":"J. Appl. Physiol."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Watenpaugh, D.E., Quatroche, A.J., Ret, C., and Fothergill, D.M. (2004). Exercise Aboard Attack Submarines: Rationale and New Options, Naval Submarine Medical Research Laboratory.","DOI":"10.1037\/e462962006-001"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"401","DOI":"10.1016\/j.ypmed.2007.07.017","article-title":"Physical activity level and health-related quality of life in the general adult population: A systematic review","volume":"45","author":"Bize","year":"2007","journal-title":"Prev. Med."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1186\/s13728-016-0050-4","article-title":"Exercise in space: The European Space Agency approach to in-flight exercise countermeasures for long-duration missions on ISS","volume":"5","author":"Petersen","year":"2016","journal-title":"Extrem. Physiol. Med."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"A92","DOI":"10.3357\/AMHP.EC12.2015","article-title":"Exercise Countermeasures on ISS: Summary and future directions","volume":"86","author":"Loerch","year":"2015","journal-title":"Aerosp. Med. Hum. Perform."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1038\/s41526-020-00111-x","article-title":"High intensity training during spaceflight: Results from the NASA Sprint Study","volume":"6","author":"English","year":"2020","journal-title":"Npj Microgravity"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"264","DOI":"10.1093\/milmed\/usac154","article-title":"Exploring the predeployment phase of an Antarctic expedition and the Brazilian Pre-Antarctic training","volume":"187","author":"Moraes","year":"2022","journal-title":"Mil. Med."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"941","DOI":"10.2165\/00007256-200636110-00003","article-title":"Exercising in environmental extremes: A greater threat to immune function?","volume":"36","author":"Walsh","year":"2006","journal-title":"Sport. Med."},{"key":"ref_12","first-page":"37","article-title":"Does moderate altitude affect VO2max in acclimatized mountain guides?","volume":"23","author":"Gatterer","year":"2021","journal-title":"High Alt. Med. Biol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1016\/j.actaastro.2021.04.003","article-title":"Speleology as an analogue to space exploration: The ESA CAVES training programme","volume":"184","author":"Sauro","year":"2021","journal-title":"Acta Astronaut."},{"key":"ref_14","first-page":"1085","article-title":"Cardiorespiratory fitness and cognitive performance before and after confinement in a nuclear submarine","volume":"56","author":"Bennett","year":"1985","journal-title":"PubMed"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1302","DOI":"10.7205\/MILMED-D-12-00016","article-title":"Physical readiness and obesity among male U.S. Navy personnel with limited exercise availability while at sea","volume":"177","author":"Gregg","year":"2012","journal-title":"Mil. Med."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1519\/SSC.0000000000000301","article-title":"Sports Injury Prevention: The role of the strength and conditioning coach","volume":"39","author":"Talpey","year":"2017","journal-title":"Strength Cond. J."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"574","DOI":"10.2519\/jospt.2020.9675","article-title":"Training Load and injury Part 1: The Devil is in the Detail\u2014Challenges to applying the current research in the training load and injury field","volume":"50","author":"Impellizzeri","year":"2020","journal-title":"J. Orthop. Sport. Phys. Ther."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1342","DOI":"10.1093\/ptj\/67.9.1342","article-title":"Intrarater reliability of manual muscle testing and hand-held dynametric muscle testing","volume":"67","author":"Wadsworth","year":"1987","journal-title":"Phys. Ther."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1312","DOI":"10.2522\/ptj.20120411","article-title":"Reference values of physical performance in Thai elderly people who are functioning well and dwelling in the community","volume":"93","author":"Thaweewannakij","year":"2013","journal-title":"Phys. Ther."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"21208","DOI":"10.1038\/s41598-021-00671-2","article-title":"Indices reflecting muscle contraction performance during exercise based on a combined electromyography and mechanomyography approach","volume":"11","author":"Fukuhara","year":"2021","journal-title":"Sci. Rep."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Hejda, J., Kut\u00edlek, P., Volf, P., Sokol, M., Leova, L., Tonner, J., Hejskov\u00e1, M., Kotolov\u00e1, V., Rozloznik, M., and Sugiarto, T. (2024, January 4\u20136). Wearable system for monitoring the physical conditions in isolated, confined and extreme environments. Proceedings of the 2024 21st International Conference on Mechatronics-Mechatronika (ME), Brno, Czech Republic.","DOI":"10.1109\/ME61309.2024.10789688"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1016\/j.actaastro.2024.10.044","article-title":"DIANA: An underwater analog space mission","volume":"226","author":"Sokol","year":"2025","journal-title":"Acta Astronaut."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"358","DOI":"10.1249\/MSS.0b013e3182a62f85","article-title":"Integrated resistance and aerobic exercise protects fitness during bed rest","volume":"46","author":"Downs","year":"2014","journal-title":"Med. Sci. Sport. Exerc."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2185","DOI":"10.1152\/japplphysiol.00346.2003","article-title":"Skeletal muscle unweighting: Spaceflight and ground-based models","volume":"95","author":"Adams","year":"2003","journal-title":"J. Appl. Physiol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"294","DOI":"10.1007\/s00421-004-1172-8","article-title":"Knee extensor and plantar flexor muscle size and function following 90 days of bed rest with or without resistance exercise","volume":"93","author":"Alkner","year":"2004","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1249\/MSS.0b013e3181e4f161","article-title":"Musculoskeletal adaptations to training with the advanced resistive exercise device","volume":"43","author":"Loehr","year":"2011","journal-title":"Med. Sci. Sport. Exerc."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"A14","DOI":"10.3357\/AMHP.EC03.2015","article-title":"Physical training for long-duration spaceflight","volume":"86","author":"Loehr","year":"2015","journal-title":"Aerosp. Med. Hum. Perform."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Abeln, V., Fomina, E., Popova, J., Braunsmann, L., Koschate, J., M\u00f6ller, F., Fedyay, S., Vassilieva, G., Schneider, S., and Str\u00fcder, H. (2022). Chronic, acute and protocol-dependent effects of exercise on psycho-physiological health during long-term isolation and confinement. BMC Neurosci., 23.","DOI":"10.1186\/s12868-022-00723-x"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Majumder, S., Mondal, T., and Deen, M.J. (2017). Wearable sensors for remote health monitoring. Sensors, 17.","DOI":"10.3390\/s17010130"},{"key":"ref_30","first-page":"13","article-title":"European recommendations for surface electromyography","volume":"8","author":"Hermens","year":"1999","journal-title":"Roessingh Res. Dev."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1123\/jab.13.2.135","article-title":"The use of surface electromyography in biomechanics","volume":"13","year":"1997","journal-title":"J. Appl. Biomech."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1689","DOI":"10.3758\/s13428-020-01516-y","article-title":"NeuroKit2: A Python toolbox for neurophysiological signal processing","volume":"53","author":"Makowski","year":"2021","journal-title":"Behav. Res. Methods"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"e12794","DOI":"10.7717\/peerj.12794","article-title":"Should I use fixed effects or random effects when I have fewer than five levels of a grouping factor in a mixed-effects model?","volume":"10","author":"Gomes","year":"2022","journal-title":"PeerJ"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Bellisle, R., Bjune, C., and Newman, D. (2020, January 20\u201324). Considerations for wearable sensors to monitor physical performance during spaceflight intravehicular activities. Proceedings of the 2020 42nd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), Montreal, QC, Canada.","DOI":"10.1109\/EMBC44109.2020.9175674"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Mekruksavanich, S., and Jitpattanakul, A. (2020, January 11\u201314). Exercise activity recognition with surface electromyography sensor using machine learning approach. Proceedings of the 2020 Joint International Conference on Digital Arts, Media and Technology with ECTI Northern Section Conference on Electrical, Electronics, Computer and Telecommunications Engineering (ECTI DAMT & NCON), Pattaya, Thailand.","DOI":"10.1109\/ECTIDAMTNCON48261.2020.9090711"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Ravizza, M., Giani, L., Sheiban, F.J., Pedrocchi, A., DeWitt, J., and Ferrigno, G. (2023). IMU-based classification of resistive exercises for real-time training monitoring on board the international space station with potential telemedicine spin-off. PLoS ONE, 18.","DOI":"10.1371\/journal.pone.0289777"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"56","DOI":"10.52082\/jssm.2021.56","article-title":"Electromyographic comparison of five lower-limb muscles between single-and multi-joint exercises among trained men","volume":"20","author":"Stien","year":"2021","journal-title":"J. Sport. Sci. Med."},{"key":"ref_38","first-page":"e9341","article-title":"Recommendations for assessment of the reliability, sensitivity, and validity of data provided by wearable sensors designed for monitoring physical activity","volume":"6","author":"Fuss","year":"2018","journal-title":"JMIR MHealth UHealth"},{"key":"ref_39","unstructured":"Naik, G.R. (2012). The Usefulness of Mean and Median Frequencies in Electromyography Analysis. Computational Intelligence in Electromyography Analysis: A Perspective on Current Applications and Future Challenges, InTech. Chapter 8."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Amin, A.B., Asabre, E., Sahay, A., Razaghi, S., and Noh, Y. (2023, January 24\u201327). Feasibility testing of wearable device for musculoskeletal monitoring during aquatic therapy and rehabilitation. Proceedings of the 2023 45th Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), Sydney, Australia.","DOI":"10.1109\/EMBC40787.2023.10340390"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"334","DOI":"10.1016\/j.bspc.2015.02.009","article-title":"Current state of digital signal processing in myoelectric interfaces and related applications","volume":"18","author":"Hakonen","year":"2015","journal-title":"Biomed. Signal Process. Control"}],"container-title":["Methods and Protocols"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2409-9279\/9\/1\/15\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,21]],"date-time":"2026-01-21T09:18:00Z","timestamp":1768987080000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2409-9279\/9\/1\/15"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,21]]},"references-count":41,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["mps9010015"],"URL":"https:\/\/doi.org\/10.3390\/mps9010015","relation":{},"ISSN":["2409-9279"],"issn-type":[{"value":"2409-9279","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,21]]}}}